The present invention relates to a computer system to store a large amount of data and more particularly to a technology for migrating data.
In recent years the amount of data handled by computer systems managed by corporations, local governments, government and municipal offices and financial institutions is increasing year by year. The increase in the amount of data is currently dealt with by adding new storage systems (storage devices) or migrating data among existing storage systems.
An addition of a plurality of storage systems to a computer system as the amount of data to be managed increases results in the computer system becoming complicated in configuration. As one technology for solving this problem there is a virtualization of a computer system. The virtualization of computer system is a technology that makes a plurality of networked storage systems virtually function as if they are a logically single computer system. The virtualization of the computer system can also integrate operation managements of the networked storage systems into a single operation management, contributing to a reduced management cost.
The application of the computer system virtualization technology allows volumes of the computer system (logical or physical unit storage areas for data) to be classified into a plurality of storage layers by using characteristics such as performance and kind as conditions. For example, JP-A-2006-99748 discloses a technology that locates data in an optimum storage system according to the kind and the date of generation of the data stored in volumes. The volumes can be grouped according to the data kind and generation date so that the data can be relocated or migrated at one time.
The technology described in JP-A-2006-99748, however, does not consider an execution sequence within the group in the process of data migration. Thus, if a plurality of volumes to be migrated share the same physical resources, such as physical disks and ports, there will be conflicting accesses to one location, prolonging the migration processing.
The present invention has been accomplished to overcome the above problem and it is an object of this invention to provide a technology which, when migrating a plurality of volumes (of data: this is omitted in the explanations that follow) as one group, avoids conflicting accesses to physical resources and parallelly executes migration operations to speed up the migration of volumes.